In an image display device, for example, a cathode ray tube display device (CRT), a plasma display (PDP), an electroluminescence display (ELD) or a liquid crystal display device (LCD), an antireflective film is ordinarily provided on the outermost surface of the display for reducing reflectivity using the principle of optical interference, in order to prevent contrast reduction due to the reflection of the outside light or reflection of an image. Thus, the antireflective film is required to have a high antifouling property against a fat or oil component, for example, a fingerprint or sebum, high physical strength (for example, scratch resistance), high transmittance, chemical resistance and weather resistance (for example, moisture/heat resistance or light resistance). In addition to the high antireflective performance.
As the antireflective film, a film having a single optical interference layer is known. However, from the standpoint of achieving more reduction of reflectivity, a multilayer type antireflective film having a plurality of optical interference layers, for example, a low refractive index layer, a medium refractive index layer or a high refractive index layer has been developed at present.
Such a multilayer type antireflective film can achieve the reduction of reflectivity, but when the layer thickness or refractive index of each of the layers is fluctuated, the reflected color may tend to change. In particular, when a fingerprint or sebum is attached on the surface of a coated film, even if it is wiped off, some residue of the fat or oil component, if any, remains, and thus, it is noticeable because the attachment trace is more readily recognized as the change in the tint based on the change in the refractive index in comparison with the single layer antireflective film, thereby reducing the visibility of the image. Therefore, in a multilayer type antireflective film, high antifouling property against a fat or oil component, for example, a fingerprint or sebum is particularly required.
As a technology for imparting the antifouling property, there has been ordinarily known a method of reducing the surface free energy of a coated film surface using a silicone compound having a polydimethylsiloxane structure or a fluorine-based compound. For example, it is proposed that a compound having a long-chain perfluoropolyether chain (PFPE) and a polyfunctional polymerizable unsaturated group is used so as to impart an antifouling performance (see, for example, JP-A-2009-256597 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”) and Japanese Patent No. 4,556,151).
However, such a compound is a compound having two kinds of repeating units of a repeating unit represented by —(CF2CF2O)m— and a repeating unit represented by —(CF2O)n— because of using as a raw material, PFPE (FLUOROLINK D, produced by Solvay Solexis, Inc.). FLUOROLINK D is presented by HOCH2CF2O(CF2CF2O)m(CF2O)nCF2CF2OH.
Although the repeating structure is represented by —(CF2CF2O)n— in the structure of Compound 1 described in Paragraph No. [0020] of JP-A-2009-256597, it is understood that the repeating structure has been incorrectly described and in fact, the repeating structure of Compound 1 of JP-A-2009-256597 is composed of two kinds of repeating units of a repeating unit represented by —(CF2CF2O)m— and a repeating unit represented by —(CF2O)n—.
Taking into consideration of increase in the surface tension reducing ability due to increase in hydrophobic interaction between the PFPE structures, it is desired that the PFPE structure is a single structure, for example, —(CF2CF2O)m— structure. However, it is difficult to obtain a repeating structure composed of only —(CF2CF2O)m— structure by the production process of FLUOROLINK D as described in the production scheme shown below (see, for example, Fusso Kagaku Nyumon; Kiso to Oyo no Siazensen 2010 (Introduction to Fluorine Chemistry: Frontline of Fundament and Application 2010)).

Further, in order to impart the antifouling property to a low refractive index layer, further improvements in reduction of refractive index, antifouling property and scratch resistance have been required.